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FAO Meteorology Equations #168

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28 changes: 24 additions & 4 deletions ncl/ncl_entries/meteorology.ipynb
Original file line number Diff line number Diff line change
Expand Up @@ -78,7 +78,15 @@
"source": [
"## daylight_fao56\n",
"\n",
"NCL's `daylight_fao56` calculates the maximum number of daylight hours as described in the Food and Agriculture Organization (FAO) Irrigation and Drainage Paper 56 [(Chapter 3, Equation 34)](https://www.fao.org/4/X0490E/x0490e07.htm#chapter%203%20%20%20meteorological%20data) {footcite}`allan_fao_1998`"
"NCL's `daylight_fao56` calculates the maximum number of daylight hours as described in the Food and Agriculture Organization (FAO) Irrigation and Drainage Paper 56 [(Chapter 3, Equation 34)](https://www.fao.org/4/X0490E/x0490e07.htm#chapter%203%20%20%20meteorological%20data) {footcite}`allan_fao_1998`\n",
"\n",
"Where the maximum number of daylight hours, N, is calculated as:\n",
"\n",
"{math}`N = \\frac{24}{{\\pi}} {\\omega}_{s}`\n",
"\n",
"Where {math}`{\\omega}_{s}` is the sunset hour angle in radians [(Chapter 3, Equation 25)](https://www.fao.org/4/X0490E/x0490e07.htm#chapter%203%20%20%20meteorological%20data) {footcite}`allan_fao_1998` which is calculated from the latitude of the observer on Earth ({math}`\\phi`) and the sun's declination ({math}`\\delta`):\n",
"\n",
"{math}`{\\omega}_{s} = arccos[-tan({\\phi})tan({\\delta})]`"
]
},
{
Expand Down Expand Up @@ -125,7 +133,11 @@
"source": [
"## satvpr_temp_fao56\n",
"\n",
"NCL's `satvpr_temp_fao56` calculates saturation vapor pressure using temperature as described in the Food and Agriculture Organization (FAO) Irrigation and Drainage Paper 56 [(Chapter 3, Equation 11)](https://www.fao.org/4/x0490e/x0490e07.htm) {footcite}`allan_fao_1998`"
"NCL's `satvpr_temp_fao56` calculates saturation vapor pressure using temperature as described in the Food and Agriculture Organization (FAO) Irrigation and Drainage Paper 56 [(Chapter 3, Equation 11)](https://www.fao.org/4/x0490e/x0490e07.htm) {footcite}`allan_fao_1998`\n",
"\n",
"Where the saturation vapor pressure, {math}`e^°` (kPa), at air temperature, {math}`T` (°C), is calculated as:\n",
"\n",
"{math}`e^°(T) = 0.6108 {\\exp}[\\frac{17.27T}{T + 237.3}]`"
]
},
{
Expand Down Expand Up @@ -169,7 +181,11 @@
"source": [
"## satvpr_tdew_fao56\n",
"\n",
"NCL's `satvpr_tdew_fao56` calculates the actual saturation vapor pressure using dewpoint temperature as described in the Food and Agriculture Organization (FAO) Irrigation and Drainage Paper 56 [(Chapter 3, Equation 14)](https://www.fao.org/4/x0490e/x0490e07.htm) {footcite}`allan_fao_1998`"
"NCL's `satvpr_tdew_fao56` calculates the actual saturation vapor pressure using dewpoint temperature as described in the Food and Agriculture Organization (FAO) Irrigation and Drainage Paper 56 [(Chapter 3, Equation 14)](https://www.fao.org/4/x0490e/x0490e07.htm) {footcite}`allan_fao_1998`\n",
"\n",
"Where the actual vapor pressure, {math}`e_{a}` (kPa), is saturation vapor pressure at a specific dewpoint temperature, {math}`T_{dew}` (°C), which is calculated as:\n",
"\n",
"{math}`e_{a} = e^°(T_{dew}) = 0.6108 {\\exp}[\\frac{17.27 T_{dew}}{T_{dew} + 237.3}]`"
]
},
{
Expand Down Expand Up @@ -206,7 +222,11 @@
"source": [
"## satvpr_slope_fao56\n",
"\n",
"NCL's `satvpr_slope_fao56` calculates the slope of the saturation vapor pressure curve as described in the Food and Agriculture Organization (FAO) Irrigation and Drainage Paper 56 [(Chapter 3, Equation 13)](https://www.fao.org/4/x0490e/x0490e07.htm) {footcite}`allan_fao_1998`"
"NCL's `satvpr_slope_fao56` calculates the slope of the saturation vapor pressure curve as described in the Food and Agriculture Organization (FAO) Irrigation and Drainage Paper 56 [(Chapter 3, Equation 13)](https://www.fao.org/4/x0490e/x0490e07.htm) {footcite}`allan_fao_1998`\n",
"\n",
"Where the slope of saturation vapor pressure curve, {math}`{\\Delta}` (kPa), at air temperature {math}`T` (°C) is calculated as:\n",
"\n",
"{math}`{\\Delta} = \\frac{4098 (0.6108 {\\exp}[\\frac{17.27T}{T + 237.3}])}{(T + 237.3)^2}`"
]
},
{
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